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