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