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