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