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