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)(11,14,17,20)(12,15,19,22)(18,21,23,24)(25,26,30,33)(27,34,35,40)(28,32,29,37)(31,38,39,36)(9,11)(10,14)(12,18)(13,17)(15,21)(16,20)(19,23)(22,24)(25,27,30,35)(26,31,33,39)(28,36,29,38)(32,40,37,34)(2,5)(6,8)(11,17)(12,19)(14,20)(15,22)(25,26)(27,31)(28,37)(29,32)(30,33)(34,36)(35,39)(38,40) involution — undirected(9,12,13,19)(10,15,16,22)(11,18,17,23)(14,21,20,24)(27,35)(31,39)(34,40)(36,38)(1,3,4,7)(2,6,5,8)(11,17)(14,20)(18,23)(21,24)(25,28,30,29)(26,32,33,37)(27,36,35,38)(31,40,39,34)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.