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