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