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