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