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