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