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