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