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