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