One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,7)(3,6,8,4)(9,10,15,19)(11,12,22,16)(13,23,21,17)(14,18,20,24)(25,26,32,29)(27,33,37,30)(28,31,34,39)(35,40,38,36)(1,3)(2,6)(4,7)(5,8)(9,11)(10,16)(12,19)(13,20)(14,21)(15,22)(17,24)(18,23)(25,27,32,37)(26,33,29,30)(28,38,34,35)(31,36,39,40)(1,2)(3,4)(5,7)(6,8)(9,12,15,16)(10,11,19,22)(13,18,21,24)(14,17,20,23)(25,28,32,34)(26,31,29,39)(27,35,37,38)(30,36,33,40)(1,3,5,8)(2,6,7,4)(9,12)(10,11)(13,18)(14,23)(15,16)(17,20)(19,22)(21,24)(25,29,32,26)(27,30,37,33)(28,31,34,39)(35,40,38,36)(1,2)(3,6)(4,8)(5,7)(9,13)(10,17)(11,20)(12,18)(14,22)(15,21)(16,24)(19,23)(25,30)(26,27)(28,36)(29,37)(31,35)(32,33)(34,40)(38,39) involution — undirected(1,4,5,6)(2,3,7,8)(9,14,15,20)(10,18,19,24)(11,21,22,13)(12,17,16,23)(25,31)(26,34)(27,36)(28,29)(30,38)(32,39)(33,35)(37,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.