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