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