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