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