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