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)(11,20)(12,17)(13,18)(14,27)(15,19)(16,23)(21,36)(22,30)(24,35)(25,32)(26,34)(28,33)(29,39)(31,37)(38,40)(9,11,15,24)(10,16,19,30)(12,21,26,38)(13,23,14,22)(17,31,34,29)(18,35,27,20)(25,39,28,37)(32,36,33,40)(1,3,4,8)(2,5,6,7)(9,12)(10,17)(11,21)(13,25)(14,28)(15,26)(16,29)(18,32)(19,34)(20,36)(22,37)(23,39)(24,38)(27,33)(30,31)(35,40)(9,12)(10,17)(11,21)(13,25)(14,28)(15,26)(16,29)(18,32)(19,34)(20,36)(22,37)(23,39)(24,38)(27,33)(30,31)(35,40) involution — undirected(9,13,15,14)(10,18,19,27)(11,22,24,23)(12,25,26,28)(16,20,30,35)(17,32,34,33)(21,37,38,39)(29,36,31,40)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.