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