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