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