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