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