One vertex per element, one color per generator, with an edge from x to x·s.
(10,13)(11,19)(12,22)(18,24)(25,26,31,30)(27,34,33,29)(28,32,36,38)(35,40,39,37)(1,2,5,4)(3,7,8,6)(9,10,15,13)(11,20,19,16)(12,23,22,17)(14,18,21,24)(28,36)(32,38)(35,39)(37,40)(2,4)(6,7)(9,11)(10,16)(12,21)(13,20)(14,22)(15,19)(17,24)(18,23)(25,27)(26,29)(28,35)(30,34)(31,33)(32,37)(36,39)(38,40) involution — undirected(1,3)(2,6)(4,7)(5,8)(9,12,15,22)(10,17,13,23)(11,21,19,14)(16,24,20,18)(25,28)(26,32)(27,35)(29,37)(30,38)(31,36)(33,39)(34,40)(9,13,15,10)(11,20,19,16)(12,23,22,17)(14,24,21,18)(25,29,31,34)(26,33,30,27)(28,37,36,40)(32,39,38,35)(1,4,5,2)(3,7,8,6)(9,14,15,21)(10,18,13,24)(11,22,19,12)(16,23,20,17)(25,30,31,26)(27,34,33,29)(28,38,36,32)(35,40,39,37)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.