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