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