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