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