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