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