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)(11,15)(12,18)(13,21)(14,16)(17,20)(19,24)(22,23)(25,26)(27,28)(29,32)(30,38)(31,33)(34,39)(35,40)(36,37)(2,3)(6,7)(9,11,14,20)(10,15,16,17)(12,21,23,19)(13,22,24,18)(25,27,31,29)(26,32,33,28)(30,35,39,37)(34,40,38,36)(10,16)(11,20)(18,22)(19,21)(26,33)(28,32)(34,38)(36,40) involution — undirected(1,2,5,3)(4,6,8,7)(9,11)(10,17)(12,21)(13,22)(14,20)(15,16)(18,24)(19,23)(25,28,31,32)(26,27,33,29)(30,36,39,40)(34,35,38,37)(1,3,5,2)(4,6,8,7)(9,12)(10,18)(11,21)(13,15)(14,23)(16,22)(17,24)(19,20)(25,29,31,27)(26,32,33,28)(30,35,39,37)(34,36,38,40)(1,4)(2,6)(3,7)(5,8)(9,13,14,24)(10,19,16,21)(11,22,20,18)(12,17,23,15)(25,30,31,39)(26,34,33,38)(27,35,29,37)(28,36,32,40)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.