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