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