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