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