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