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