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