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