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